I have been in Vietnam for two weeks and have run into no scams. If you Use your head and watch your wallet you have nothing to fear.
I was told by my guide to watch bags over the arm facing the street. motor bikes will come by and snatch them. do not hold on to it they will drag you until you let go.
The markets are full of knock offs but prices are dirt cheap. I got a “Rolex” for 30.00, just for fun. You bargain, start at 50% of what they ask and don’t act to interested. when you walk away they will follow and the price drops quickly.
Every person I have met is very nice. I have been to Vietnam several times and have only had great experiences. You will love this country, happy photo taking.